[meteorite-list] Chip Sniffs Out The Building Blocks of Life

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Jan 18 16:00:22 2005
Message-ID: <200501182100.NAA00343_at_zagami.jpl.nasa.gov>

http://www.newscientist.com/article.ns?id=dn6889

Chip sniffs out the building blocks of life
New Scientist
Kelly Young
January 18, 2005

A small glass chip that could one day help sniff out the building blocks
of life on Mars has successfully detected sparse organic compounds in
barren, Mars-like environments on Earth.

In preparation for future robotic missions, scientists tested the Mars
Organic Analyzer (MOA) with samples collected from two deserts thought
to closely match conditions on the Red Planet - the Atacama Desert in
Chile and the Panoche Valley in California, US.

The Atacama Desert can go years without rain and its high elevation
means it soaks up lots of ultraviolet light. This makes for a highly
oxidising environment, similar to that found on Mars.

"It is essentially the most barren place we can find, so if we can
detect signs of life - present or past - in that region, then at
least we are certain of the ability of our instrumentation to
perform with the same sensitivity on Mars," says Alison Skelley,
at the University of California, Berkeley, US, who led the study.

The briefcase-sized instrument, housing the four-layer glass
microdevice, successfully detected amino acids in the range of 10 to 500
parts per billion from soil samples collected in the desert.

Parts per trillion

In the Panoche Valley, researchers coupled the MOA with another
instrument called the Mars Organic Detector (MOD), which is how it would
be used on Mars. Together, the instruments found amino acids in the
range of 70 parts per trillion to 100 parts per billion in jarosite, a
mineral that has already been detected on Mars.

The research is important to help scientists work out whether life could
ultimately survive on Mars. Life in human terms requires liquid water,
organic molecules and a source of energy.

In 1976, NASA's Viking landers carried instruments that checked for
organic molecules on Mars, but failed to find anything. Scientists now
suspect that this was because of the planet's highly oxidising
environment, which would change any organic molecules into a form that
would have been undetectable by Viking's instruments.

The MOA takes into account this highly oxidising environment and is 1000
times more sensitive than Viking's instruments.

Dying to detect

A probe carrying the device would scoop up a sample of soil and place it
into the MOD, which would heat up the sample to 500?C. This heat should
cause any organic molecules in the rock to turn to gas, which could then
be condensed onto a cold, dye-covered surface.

The dye attaches to a particular reactive group, present on all amino
acids, so if any of these molecules are present they become labelled.
Any fluorescence seen by the detector indicates the presence of an amino
acid. At this stage the MOA takes over. Through a series of tiny pumps
and channels, the analyser can separate out different amino acids.

The MOA still has several engineering challenges ahead, say its
designers. It needs to be fully automated and able to handle 80 to 100
soil samples.

It is being considered for a European Space Agency orbiter/rover
mission, called ExoMars, which is scheduled for launch in 2009 or 2011.
But it will not be used by NASA for its next big landing mission, the
Mars Science Laboratory, set for a 2009 launch.

Instead of the Mars Organic Analyzer, the roving Mars Science Laboratory
will carry the Sample Analysis at Mars instrument suite to detect
organic compounds. It uses a gas chromatograph mass spectrometer - an
advanced version of the device flown on the Viking landers. In addition,
a laser will vaporise soil so its molecular composition can be analysed.

Journal reference: Proceedings of the National Academy of Sciences (vol
102, p 1041)
Received on Tue 18 Jan 2005 04:00:03 PM PST